[wiki] Shellcheck GitHub Action Commands - **/*.sh vs find

[codecriticsceo]

I updated some of the commands in the GitHub actions wiki to use find instead of shellcheck **/*.sh. I ran some tests on a throwaway repo and found that the **/*.sh version only finds scripts that are within a single directory, e.g., suppose there is a project with the layout:

script_1.sh
dir1/script_2.sh
dir1/dir2/script_3.sh

The shellcheck **/*.sh version of the command will only find the script_2.sh file in this example, and the others will remain unlinted. Meanwhile, the find version will lint all the scripts. I think there are more cases of the **/*.sh variant, if desired I can help migrate to the find variant.

https://github.com/koalaman/shellcheck/wiki/GitHub-Actions/_compare/dd7f03302b2e07b2bc9f0cc5b2fce0fb75ac2b1d

Thanks for creating shellcheck, have used it extensively and it has helped debug some extremely challenging issues.